The National Telecommunications Information Administration (NTIA) is the executive branch's advisory agency on telecommunications issues. In the early 1980s, this agency proposed a plan to raise awareness of a single emergency telephone number to the general public. From that program, the National Emergency Number Association (NENA), a non-profit organization, was created. NENA has since become a leading organization to improving technology and developing guidelines for 9-1-1 (“911”) telephone calls (i.e., emergency telephone calls) to improve response by emergency rescue teams.
Telecommunications has been changing rapidly over the past several years, primarily since the development and growth of the mobile telephone industry and the Internet. New forms of telecommunications have been developing as well Tradition telecommunications were performed over the public switch telephone network (PSTN). A system to maintain location of subscribers of telecommunications companies operating on the PSTN was developed. Determining the location of subscribers of the telecommunication companies was relatively easy as the locations were known by the telecommunications companies or carriers due to installing the telephones, establishing billing, or otherwise. With the new forms of telecommunications, these telephones and devices (e.g., Internet Protocol (IP) telephones or voice over IP (VoIP) telephones) operate over the Internet and have subscriptions with non-traditional telecommunications carriers, such as Vonage®. When VoIP telephones are not purchased from the telecommunications carriers, but rather purchased from a retail store, there is no record of physical location where the VoIP telephone is being used. Not leaving location information for the VoIP telephone is a problem for 911 telephone calls as the location information cannot automatically be communicated to a 911 operator at a public-safety answering point.
In response to the problem of the VoIP telephones not having addresses associated with them for 911 telephone calls, via databases or otherwise, NENA has encouraged the telecommunications industry to develop a system to provide public-safety answering points (PSAPs) with location information for non-traditional telephone calls through the use of enhanced 911 (“E-911”). To accommodate the need to provide location information to public-safety answering points during E-911 telephone calls, a number of solutions have been developed by different telecommunications groups.
FIG. 1 is a block diagram of a conventional system configuration for storing and reporting physical locations (e.g., street addresses) of VoIP telephones to public-safety answering points. As shown, there are two networks in communication with one another, an IP network 102 and the PSTN 104. Within the IP network 102 is a VoIP telephone 106 and a call server 108, which receives calls from the VoIP telephone. Between the IP network 102 and PSTN 104 is an emergency service gateway 110 that converts data packets as communicated over VoIP network 102 into signals for communication over PSTN 104. Within the PSTN 104 are selective routers 112 and public-safety answering points 114. Although only one selective router 112 and public-safety answering point 114 are shown, it should be understood that there are many selective routers 112 and thousands of public-safety answering points located on the PSTN 104 in the United States. An automated location identifier (ALI) 116 is a system that enables the automatic display at the public-safety answering point of a caller's telephone number, the address/location of the telephone, and supplementary emergency services information. A VoIP positioning center (VPC) 118 is a database that maintains and manages emergency servers routing keys (ESRK), emergency service query keys (ESQK), and locations of VoIP telephones. The VoIP position center 118 is located on the IP network 102 and is configured to communicate over the PSTN 104.
In operation, when a user places an E-911 telephone call using the VoIP telephone 106, a signal 120, including a telephone number associated with a VoIP telephone 106, is communicated to the call server 108. The call server 108, in response, communicates the signal 120 to the VoIP position center 118. In response, the VoIP position center 118 communicates a signal 122, including the telephone number, emergency service routing key (ESQK), which causes the call to be routed to a local selective router and emergency service query key (ESQK), which causes the correct location information to be queried for display at the public-safety answering point 114 to the call server 108. The call server 108, in turn, communicates the signal 122 to the emergency service gateway 110. Based on the emergency service routing key, the emergency service gateway 110 communicates the signal 122 to the appropriate selective router 112 in an area near the VoIP telephone 106. The selective router 112 determines which public-safety answering point 114 is physically located near the VoIP telephone 106 and communicates the telephone number and emergency service query key in a signal 124 to the public-safety answering point 114.
The public-safety answering point 114 communicates the emergency service query key in a signal 126 to the automated location identifier 116, which, in turn, communicates the emergency service query key to the VoIP positioning center 118. The VoIP positioning center 118 looks up the address associated with the VoIP telephone 116 in a database using the emergency service query key and communicates the location, which may include an address, apartment, office number, or other information associated with the VoIP telephone 106, in a signal 128 to the automated location identifier 116. The automated location identifier 116 communicates the location information to the public-safety answering point 114 for display to an operator who answers the telephone call from the user of the VoIP telephone 106. The operator is then able to determine the specific location of the VoIP telephone 106 and communicate that information to emergency services, such as firefighters and policemen, who respond to the E-911 telephone calls.
There are problems that exist with the configuration of system 100. First, the VoIP positioning center 118 is a database that is very expensive to create and maintain. Second, communications between the automated location identifier 116 and VoIP positioning center 118 require two dedicated trunks, one for communications from the automated location identifier 116 to the VoIP positioning center 118 and one from the VoIP positioning center 118 to the automated location identifier 116. It is understood that the operation for deploying and maintaining these trunks is expensive. Third, entering information into a database located at the VoIP positioning center 118 is complicated. For at least these reasons, there is a need for an improved system for maintaining location information associated with VoIP telephones.